KUALA LUMPUR, Malaysia -- Former Malaysian Prime Minister Mahathir Mohamad released his memoir Tuesday, defending decisions he made during a 22-year rule that critics say was marred by human rights abuses.

Mahathir, who was one of Asia's longest-serving leaders when he retired in 2003, maintains in his book that his policies were in the country's best interests, but says he regrets that "the epithet 'authoritarian' appears without fail in all my detractors' assessments of me."

"I had tried my best although I cannot be a judge of my own work," the 85-year-old Mahathir says. "It is up to the people of today and the future to pass judgment."

The 800-page book - titled "A Doctor In The House," a reference to Mahathir's former medical career - hit stores in a blaze of publicity. Bookstore chain MPH displayed posters declaring the autobiography is "set to be the best-selling book of 2011."

Mahathir's frank, personal writing provides rare glimpses into every phase of his life. He recounts his childhood in a poor northern Malaysian neighborhood that "verged on being a slum," with "stinking earth drains and black scum floating on the water."

His father was a strict schoolteacher who emphasized education, spurring him to study medicine. He became politically active in the 1950s during the twilight of British colonial rule, eventually running for Parliament and winning in 1964.

After nearly 30 years in and out of government, Mahathir became Malaysia's fourth prime minister in 1981. He claims he was "a highly unlikely candidate" since his predecessors were London-trained lawyers with political pedigrees.

Mahathir devotes several chapters to his economic drive that transformed Malaysia from a rubber and tin mining economy into one of Asia's most industrialized countries. He voices pride that the Petronas Twin Towers were the world's tallest buildings in the late 1990s.

He also explains his choices during political crises in the 1980s that led to the detention without trial of dozens of opposition activists, the closure of newspapers and other measures that curtailed the independence of the judiciary.

"It is hard to know at such times what is required and reasonable, what is disproportionate and excessive," Mahathir writes. "We had to act, and we did."

A key chapter focuses on Mahathir's firing of his deputy, Anwar Ibrahim, in 1998 over accusations of sexual misconduct - a decision that continues to have a tremendous impact on Malaysian politics.

Anwar spent six years in prison on sodomy and abuse of power convictions before a court ordered his release. He now leads Malaysia's opposition and is embroiled in another trial for allegedly sodomizing a male aide. He claims all the charges are false.

"Anwar should have been the prime minister of Malaysia today. But if he is not, it is because of his own actions," Mahathir writes. "I may have made many mistakes, but removing Anwar was not one of them."